Add and fix -Wconversion errors

CMakeLists.txt

@@ -196,10 +196,16 @@ add_compile_options(
     $<$<COMPILE_LANG_AND_ID:C,Clang,GNU>:-Wall>
     $<$<COMPILE_LANG_AND_ID:C,Clang,GNU>:-Wextra>
     $<$<COMPILE_LANG_AND_ID:C,Clang,GNU>:-Werror>
+    $<$<COMPILE_LANG_AND_ID:C,Clang,GNU>:-Wconversion>
     $<$<COMPILE_LANG_AND_ID:C,Clang,GNU>:-Wunused-variable>
     $<$<COMPILE_LANG_AND_ID:C,Clang>:-Weverything>
 
-    # TODO: Add in other Compilers here.
+    # Suppressions required to build clean with clang.
+    $<$<COMPILE_LANG_AND_ID:C,Clang>:-Wno-unused-macros>
+    $<$<COMPILE_LANG_AND_ID:C,Clang>:-Wno-padded>
+    $<$<COMPILE_LANG_AND_ID:C,Clang>:-Wno-missing-variable-declarations>
+    $<$<COMPILE_LANG_AND_ID:C,Clang>:-Wno-covered-switch-default>
+    $<$<COMPILE_LANG_AND_ID:C,Clang>:-Wno-cast-align>
 )
 
 ########################################################################

source/FreeRTOS_ARP.c

@@ -321,6 +321,10 @@ static TickType_t xLastGratuitousARPTime = 0U;
                                     }
                                 }
                             }
+                            else
+                            {
+                                /* do nothing, coverity happy */
+                            }
 
                             break;
 

source/FreeRTOS_BitConfig.c

@@ -200,8 +200,8 @@ uint16_t usBitConfig_read_16( BitConfig_t * pxConfig )
 
     if( xBitConfig_read_uc( pxConfig, pucData, uxNeeded ) != pdFALSE )
     {
-        usResult = ( ( ( uint16_t ) pucData[ 0 ] ) << 8 ) |
-                   ( ( ( uint16_t ) pucData[ 1 ] ) );
+        usResult = ( uint16_t ) ( ( ( ( uint16_t ) pucData[ 0 ] ) << 8 ) |
+                                  ( ( ( uint16_t ) pucData[ 1 ] ) ) );
     }
 
     return usResult;

source/FreeRTOS_DHCP.c

@@ -1654,8 +1654,8 @@
 
             ( void ) xApplicationGetRandomNumber( &( ulNumbers[ 0 ] ) );
             ( void ) xApplicationGetRandomNumber( &( ulNumbers[ 1 ] ) );
-            ucLinkLayerIPAddress[ 0 ] = ( uint8_t ) 1 + ( uint8_t ) ( ulNumbers[ 0 ] % 0xFDU ); /* get value 1..254 for IP-address 3rd byte of IP address to try. */
-            ucLinkLayerIPAddress[ 1 ] = ( uint8_t ) 1 + ( uint8_t ) ( ulNumbers[ 1 ] % 0xFDU ); /* get value 1..254 for IP-address 4th byte of IP address to try. */
+            ucLinkLayerIPAddress[ 0 ] = ( uint8_t ) ( 1 + ( ulNumbers[ 0 ] % 0xFDU ) ); /* get value 1..254 for IP-address 3rd byte of IP address to try. */
+            ucLinkLayerIPAddress[ 1 ] = ( uint8_t ) ( 1 + ( ulNumbers[ 1 ] % 0xFDU ) ); /* get value 1..254 for IP-address 4th byte of IP address to try. */
 
             EP_IPv4_SETTINGS.ulGatewayAddress = 0U;
 

source/FreeRTOS_DHCPv6.c

@@ -1011,7 +1011,7 @@ static void prvSendDHCPMessage( NetworkEndPoint_t * pxEndPoint )
                     uint16_t usLength = ( uint16_t ) pxDHCPMessage->xServerID.uxLength;
                     /* DHCPv6_Option_Server_Identifier */
                     vBitConfig_write_16( &( xMessage ), DHCPv6_Option_Server_Identifier );     /* Option is 1: Server Identifier */
-                    vBitConfig_write_16( &( xMessage ), usLength + 4U );                       /* The length is 14 */
+                    vBitConfig_write_16( &( xMessage ), ( uint16_t ) ( usLength + 4U ) );      /* The length is 14 */
                     vBitConfig_write_16( &( xMessage ), pxDHCPMessage->xServerID.usDUIDType ); /* The type of DUID: 1, 2, or 3. */
                     vBitConfig_write_16( &( xMessage ), pxDHCPMessage->xServerID.usHardwareType );
                     vBitConfig_write_uc( &( xMessage ), pxDHCPMessage->xServerID.pucID, pxDHCPMessage->xServerID.uxLength );
@@ -1263,7 +1263,7 @@ static BaseType_t prvDHCPv6_handleOption( struct xNetworkEndPoint * pxEndPoint,
                          *  - the message does not include a Client Identifier option.
                          *  - the contents of the Client Identifier option does not match the client's DUID.
                          *  - the "transaction-id" field value does not match the value the client used in its Solicit message. */
-                        ( void ) xBitConfig_read_uc( pxMessage, pxDHCPMessage->xClientID.pucID, lIDSize ); /* Link Layer address, 6 bytes */
+                        ( void ) xBitConfig_read_uc( pxMessage, pxDHCPMessage->xClientID.pucID, ( size_t ) lIDSize ); /* Link Layer address, 6 bytes */
 
                         /* Check client DUID. */
                         if( ( pxSet->uxOptionLength != dhcpIPv6_CLIENT_DUID_LENGTH ) ||

source/FreeRTOS_DNS_Parser.c

@@ -471,7 +471,7 @@
                                 /*logging*/
                                 FreeRTOS_printf( ( "prvParseDNS_HandleLLMNRRequest[%s]: type %04X\n", xSet.pcName, xSet.usType ) );
 
-                                xEndPoint.usDNSType = xSet.usType;
+                                xEndPoint.usDNSType = ( uint8_t ) xSet.usType;
                             }
                         #endif /* ( ipconfigUSE_IPv6 != 0 ) */
 
@@ -572,7 +572,7 @@
                                         ( void ) memcpy( &( pxAnswer->ulIPAddress ), xEndPoint.ipv6_settings.xIPAddress.ucBytes, ipSIZE_OF_IPv6_ADDRESS );
                                         uxDistance = ( size_t ) ( xSet.pucByte - pucNewBuffer );
                                         /* An extra 12 bytes will be sent compared to an A-record. */
-                                        usLength = ( int16_t ) sizeof( *pxAnswer ) + uxDistance + ipSIZE_OF_IPv6_ADDRESS - sizeof( pxAnswer->ulIPAddress );
+                                        usLength = ( int16_t ) ( sizeof( *pxAnswer ) + uxDistance + ipSIZE_OF_IPv6_ADDRESS - sizeof( pxAnswer->ulIPAddress ) );
                                     }
                                     else
                                 #endif /* ( ipconfigUSE_IPv6 != 0 ) */
@@ -1090,8 +1090,8 @@
                     /* Define the ASCII value of the capital "A". */
                     const uint8_t ucCharA = ( uint8_t ) 0x41U;
 
-                    ucByte = ( ( uint8_t ) ( ( pucSource[ 0 ] - ucCharA ) << 4 ) ) |
-                             ( pucSource[ 1 ] - ucCharA );
+                    ucByte = ( uint8_t ) ( ( ( pucSource[ 0 ] - ucCharA ) << 4 ) |
+                                           ( pucSource[ 1 ] - ucCharA ) );
 
                     /* Make sure there are no trailing spaces in the name. */
                     if( ( ucByte == ( uint8_t ) ' ' ) && ( pucTarget[ 1 ] == 0U ) )

source/FreeRTOS_IPv4.c

@@ -457,8 +457,8 @@ eFrameProcessingResult_t prvCheckIP4HeaderOptions( NetworkBufferDescriptor_t * c
             pxIPHeader->usLength = FreeRTOS_htons( FreeRTOS_ntohs( pxIPHeader->usLength ) - optlen );
 
             /* Rewrite the Version/IHL byte to indicate that this packet has no IP options. */
-            pxIPHeader->ucVersionHeaderLength = ( pxIPHeader->ucVersionHeaderLength & 0xF0U ) | /* High nibble is the version. */
-                                                ( ( ipSIZE_OF_IPv4_HEADER >> 2 ) & 0x0FU );
+            pxIPHeader->ucVersionHeaderLength = ( uint8_t ) ( ( pxIPHeader->ucVersionHeaderLength & 0xF0U ) | /* High nibble is the version. */
+                                                              ( ( ipSIZE_OF_IPv4_HEADER >> 2 ) & 0x0FU ) );
         }
     #else /* if ( ipconfigIP_PASS_PACKETS_WITH_IP_OPTIONS != 0 ) */
         {

source/FreeRTOS_IPv4_Utils.c

@@ -147,7 +147,7 @@ BaseType_t prvChecksumIPv4Checks( uint8_t * pucEthernetBuffer,
         /* coverity[misra_c_2012_rule_11_3_violation] */
         pxSet->pxProtocolHeaders = ( ( ProtocolHeaders_t * ) &( pucEthernetBuffer[ pxSet->uxIPHeaderLength + ipSIZE_OF_ETH_HEADER ] ) );
         /* For IPv4, the number of bytes in IP-header + the protocol is indicated. */
-        pxSet->usProtocolBytes = pxSet->usPayloadLength - ( ( uint16_t ) pxSet->uxIPHeaderLength );
+        pxSet->usProtocolBytes = ( uint16_t ) ( pxSet->usPayloadLength - pxSet->uxIPHeaderLength );
     }
 
     return xReturn;

source/FreeRTOS_IPv6.c

@@ -145,7 +145,7 @@ const struct xIPv6_Address FreeRTOS_in6addr_loopback = { { 0, 0, 0, 0, 0, 0, 0,
             {
                 pxExtHeader = ( const IPExtHeader_IPv6_t * ) ( &( pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER + uxExtHeaderLength ] ) );
                 /* The definition of length in extension header - Length of this header in 8-octet units, not including the first 8 octets. */
-                uxExtHeaderLength += ( 8 * pxExtHeader->ucHeaderExtLength ) + 8;
+                uxExtHeaderLength += ( size_t ) ( ( 8 * pxExtHeader->ucHeaderExtLength ) + 8 );
 
                 ucNextHeader = pxExtHeader->ucNextHeader;
 
@@ -656,7 +656,7 @@ eFrameProcessingResult_t eHandleIPv6ExtensionHeaders( NetworkBufferDescriptor_t
             ( void ) memmove( pucTo, pucFrom, xMoveLen );
             pxNetworkBuffer->xDataLength -= uxRemovedBytes;
 
-            usPayloadLength -= ( uint16_t ) uxRemovedBytes;
+            usPayloadLength = ( uint16_t ) ( usPayloadLength - uxRemovedBytes );
             pxIPPacket_IPv6->xIPHeader.usPayloadLength = FreeRTOS_htons( usPayloadLength );
             eResult = eProcessBuffer;
         }

source/FreeRTOS_IPv6_Sockets.c

@@ -165,12 +165,12 @@ char cHexToChar( uint16_t usValue )
 
     if( usValue <= 9U )
     {
-        cReturn += usValue;
+        cReturn = ( char ) ( cReturn + usValue );
     }
     else if( usValue <= 15U )
     {
         cReturn = 'a';
-        cReturn += ( usValue - 10U );
+        cReturn = ( char ) ( cReturn + ( usValue - ( uint16_t ) 10 ) );
     }
     else
     {
@@ -199,7 +199,7 @@ socklen_t uxHexPrintShort( char * pcBuffer,
 {
     const size_t uxNibbleCount = 4U;
     size_t uxNibble;
-    size_t uxIndex = 0U;
+    socklen_t uxIndex = 0U;
     uint16_t usShifter = usValue;
     BaseType_t xHadNonZero = pdFALSE;
 
@@ -223,7 +223,7 @@ socklen_t uxHexPrintShort( char * pcBuffer,
             uxIndex++;
         }
 
-        usShifter <<= 4;
+        usShifter = ( uint16_t ) ( usShifter << 4 );
     }
 
     return uxIndex;

source/FreeRTOS_IPv6_Utils.c

@@ -106,7 +106,7 @@ BaseType_t prvChecksumIPv6Checks( uint8_t * pucEthernetBuffer,
             pxSet->pxProtocolHeaders = ( ( ProtocolHeaders_t * ) &( pucEthernetBuffer[ ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER + uxExtensionHeaderLength ] ) );
             pxSet->usPayloadLength = FreeRTOS_ntohs( pxSet->pxIPPacket_IPv6->usPayloadLength );
             /* For IPv6, the number of bytes in the protocol is indicated. */
-            pxSet->usProtocolBytes = pxSet->usPayloadLength - ( uint16_t ) uxExtensionHeaderLength;
+            pxSet->usProtocolBytes = ( uint16_t ) ( pxSet->usPayloadLength - uxExtensionHeaderLength );
 
             size_t uxNeeded = ( size_t ) pxSet->usPayloadLength;
             uxNeeded += ipSIZE_OF_ETH_HEADER + ipSIZE_OF_IPv6_HEADER;

source/FreeRTOS_Routing.c

@@ -1459,8 +1459,8 @@ IPv6_Type_t xIPv6_GetIPType( const IPv6_Address_t * pxAddress )
         for( xIndex = 0; xIndex < ARRAY_SIZE_X( xIPCouples ); xIndex++ )
         {
             uint16_t usAddress =
-                ( ( ( uint16_t ) pxAddress->ucBytes[ 0 ] ) << 8 ) |
-                ( ( uint16_t ) pxAddress->ucBytes[ 1 ] );
+                ( uint16_t ) ( ( ( ( uint16_t ) pxAddress->ucBytes[ 0 ] ) << 8 ) |
+                               ( ( uint16_t ) pxAddress->ucBytes[ 1 ] ) );
 
             if( ( usAddress & xIPCouples[ xIndex ].usMask ) == xIPCouples[ xIndex ].usExpected )
             {
@@ -1504,7 +1504,7 @@ const char * pcEndpointName( const NetworkEndPoint_t * pxEndPoint,
                     ( void ) FreeRTOS_inet_ntop( FREERTOS_AF_INET4,
                                                  ( const void * ) &( pxEndPoint->ipv4_settings.ulIPAddress ),
                                                  pcBuffer,
-                                                 uxSize );
+                                                 ( socklen_t ) uxSize );
                     break;
             #endif /* ( ipconfigUSE_IPv4 != 0 ) */
 
@@ -1513,7 +1513,7 @@ const char * pcEndpointName( const NetworkEndPoint_t * pxEndPoint,
                     ( void ) FreeRTOS_inet_ntop( FREERTOS_AF_INET6,
                                                  pxEndPoint->ipv6_settings.xIPAddress.ucBytes,
                                                  pcBuffer,
-                                                 uxSize );
+                                                 ( socklen_t ) uxSize );
                     break;
             #endif /* ( ipconfigUSE_IPv6 != 0 ) */
 

source/FreeRTOS_Sockets.c

@@ -574,7 +574,7 @@ static BaseType_t prvDetermineSocketSize( BaseType_t xDomain,
 
                 if( pxSocket->u.xTCP.usMSS > usDifference )
                 {
-                    pxSocket->u.xTCP.usMSS -= ( uint16_t ) usDifference;
+                    pxSocket->u.xTCP.usMSS = ( uint16_t ) ( pxSocket->u.xTCP.usMSS - usDifference );
                 }
             }
         #endif /* ipconfigUSE_IPv6 != 0 */
@@ -2843,7 +2843,7 @@ BaseType_t FreeRTOS_setsockopt( Socket_t xSocket,
 
                 if( pvOptionValue == NULL )
                 {
-                    pxSocket->ucSocketOptions &= ~( ( uint8_t ) FREERTOS_SO_UDPCKSUM_OUT );
+                    pxSocket->ucSocketOptions &= ( ( uint8_t ) ~( ( uint8_t ) FREERTOS_SO_UDPCKSUM_OUT ) );
                 }
                 else
                 {
@@ -2956,7 +2956,7 @@ BaseType_t FreeRTOS_setsockopt( Socket_t xSocket,
 static uint16_t prvGetPrivatePortNumber( BaseType_t xProtocol )
 {
     const uint16_t usEphemeralPortCount =
-        socketAUTO_PORT_ALLOCATION_MAX_NUMBER - ( socketAUTO_PORT_ALLOCATION_START_NUMBER - 1U );
+        socketAUTO_PORT_ALLOCATION_MAX_NUMBER - ( uint16_t ) ( socketAUTO_PORT_ALLOCATION_START_NUMBER - 1U );
     uint16_t usIterations = usEphemeralPortCount;
     uint32_t ulRandomSeed = 0;
     uint16_t usResult = 0;
@@ -2987,9 +2987,8 @@ static uint16_t prvGetPrivatePortNumber( BaseType_t xProtocol )
         }
 
         /* Map the random to a candidate port. */
-        usResult =
-            socketAUTO_PORT_ALLOCATION_START_NUMBER +
-            ( ( ( uint16_t ) ulRandomSeed ) % usEphemeralPortCount );
+        usResult = ( uint16_t ) ( socketAUTO_PORT_ALLOCATION_START_NUMBER +
+                                  ( ( ( uint16_t ) ulRandomSeed ) % usEphemeralPortCount ) );
 
         /* Check if there's already an open socket with the same protocol
          * and port. */
@@ -3266,23 +3265,23 @@ uint8_t ucASCIIToHex( char cChar )
 
     if( ( cValue >= '0' ) && ( cValue <= '9' ) )
     {
-        cValue -= ( char ) '0';
+        cValue = ( char ) ( cValue - ( uint8_t ) '0' );
         /* The value will be between 0 and 9. */
         ucNew = ( uint8_t ) cValue;
     }
     else if( ( cValue >= 'a' ) && ( cValue <= 'f' ) )
     {
-        cValue -= ( char ) 'a';
+        cValue = ( char ) ( cValue - ( uint8_t ) 'a' );
         ucNew = ( uint8_t ) cValue;
         /* The value will be between 10 and 15. */
-        ucNew += ( uint8_t ) 10;
+        ucNew = ( uint8_t ) ( ucNew + ( uint8_t ) 10 );
     }
     else if( ( cValue >= 'A' ) && ( cValue <= 'F' ) )
     {
-        cValue -= ( char ) 'A';
+        cValue = ( char ) ( cValue - ( uint8_t ) 'A' );
         ucNew = ( uint8_t ) cValue;
         /* The value will be between 10 and 15. */
-        ucNew += ( uint8_t ) 10;
+        ucNew = ( uint8_t ) ( ucNew + ( uint8_t ) 10 );
     }
     else
     {
@@ -3339,7 +3338,8 @@ void FreeRTOS_EUI48_ntop( const uint8_t * pucSource,
             else
             {
                 cResult = cTen; /* Either 'a' or 'A' */
-                cResult = ( char ) ( cResult + ( ucNibble - 10U ) );
+                cResult = ( char ) ( cResult + ucNibble );
+                cResult = ( char ) ( cResult - ( uint8_t ) 10U );
             }
 
             pcTarget[ uxTarget ] = cResult;

source/FreeRTOS_TCP_IP.c

@@ -184,7 +184,7 @@
                                                          ( unsigned ) ( uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER ) ) );
                             }
 
-                            prvTCPReturnPacket( pxSocket, pxSocket->u.xTCP.pxAckMessage, uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER, ipconfigZERO_COPY_TX_DRIVER );
+                            prvTCPReturnPacket( pxSocket, pxSocket->u.xTCP.pxAckMessage, ( uint32_t ) ( uxIPHeaderSizeSocket( pxSocket ) + ipSIZE_OF_TCP_HEADER ), ipconfigZERO_COPY_TX_DRIVER );
 
                             #if ( ipconfigZERO_COPY_TX_DRIVER != 0 )
                                 {

source/FreeRTOS_TCP_Reception.c

@@ -331,14 +331,14 @@
                          */
                         if( pucPtr[ 0U ] == tcpTCP_OPT_SACK_A )
                         {
-                            ucLen -= 2U;
+                            ucLen = ( uint8_t ) ( ucLen - 2U );
                             lIndex += 2;
 
                             while( ucLen >= ( uint8_t ) 8U )
                             {
                                 prvReadSackOption( pucPtr, ( size_t ) lIndex, pxSocket );
                                 lIndex += 8;
-                                ucLen -= 8U;
+                                ucLen = ( uint8_t ) ( ucLen - 8U );
                             }
 
                             /* ucLen should be 0 by now. */

source/FreeRTOS_TCP_Utils_IPV6.c

@@ -93,7 +93,7 @@ void prvSocketSetMSS_IPV6( FreeRTOS_Socket_t * pxSocket )
                 }
             #endif
 
-            ulMSS -= uxDifference;
+            ulMSS = ( uint32_t ) ( ulMSS - uxDifference );
             IPv6_Type_t eType = xIPv6_GetIPType( &( pxSocket->u.xTCP.xRemoteIP.xIP_IPv6 ) );
 
             if( eType == eIPv6_Global )

source/FreeRTOS_TCP_WIN.c

@@ -1862,7 +1862,7 @@
                 if( ( pxSegment->u.bits.ucTransmitCount == MAX_TRANSMIT_COUNT_USING_LARGE_WINDOW ) &&
                     ( pxWindow->xSize.ulTxWindowLength > ( 2U * ( ( uint32_t ) pxWindow->usMSS ) ) ) )
                 {
-                    uint16_t usMSS2 = pxWindow->usMSS * 2U;
+                    uint16_t usMSS2 = ( uint16_t ) ( pxWindow->usMSS * 2U );
                     FreeRTOS_debug_printf( ( "ulTCPWindowTxGet[%u - %u]: Change Tx window: %u -> %u\n",
                                              pxWindow->usPeerPortNumber,
                                              pxWindow->usOurPortNumber,

source/portable/NetworkInterface/Common/phyHandling.c

@@ -238,7 +238,7 @@ BaseType_t xPhyDiscover( EthernetPhy_t * pxPhyObject )
             pxPhyObject->fnPhyRead( xPhyAddress, phyREG_02_PHYSID1, &ulUpperID );
             ulPhyID = ( ( ( uint32_t ) ulUpperID ) << 16 ) | ( ulLowerID & 0xFFF0U );
 
-            pxPhyObject->ucPhyIndexes[ pxPhyObject->xPortCount ] = xPhyAddress;
+            pxPhyObject->ucPhyIndexes[ pxPhyObject->xPortCount ] = ( uint8_t ) xPhyAddress;
             pxPhyObject->ulPhyIDs[ pxPhyObject->xPortCount ] = ulPhyID;
 
             pxPhyObject->xPortCount++;

source/portable/NetworkInterface/linux/NetworkInterface.c

@@ -861,7 +861,7 @@ static void * prvLinuxPcapSendThread( void * pvParam )
             FreeRTOS_debug_printf( ( "Sending  ========== > data pcap_sendpadcket %lu\n", xLength ) );
             print_hex( ucBuffer, xLength );
 
-            if( pcap_sendpacket( pxOpenedInterfaceHandle, ucBuffer, xLength ) != 0 )
+            if( pcap_sendpacket( pxOpenedInterfaceHandle, ucBuffer, ( int ) xLength ) != 0 )
             {
                 FreeRTOS_printf( ( "pcap_sendpackeet: send failed %d\n", ulPCAPSendFailures ) );
                 ulPCAPSendFailures++;

test/build-combination/Common/main.c

@@ -242,7 +242,7 @@ UBaseType_t uxRand( void )
 
 BaseType_t xApplicationGetRandomNumber( uint32_t * pulNumber )
 {
-    *pulNumber = uxRand();
+    *pulNumber = ( uint32_t ) uxRand();
 
     return pdTRUE;
 }
@@ -286,7 +286,7 @@ extern uint32_t ulApplicationGetNextSequenceNumber( uint32_t ulSourceAddress,
     ( void ) ulDestinationAddress;
     ( void ) usDestinationPort;
 
-    return uxRand();
+    return ( uint32_t ) uxRand();
 }
 
 void vApplicationGetTimerTaskMemory( StaticTask_t ** ppxTimerTaskTCBBuffer,
@@ -365,6 +365,6 @@ void vApplicationPingReplyHook( ePingReplyStatus_t eStatus,
     /* DHCPv6 needs a time-stamp, seconds after 1970. */
     uint32_t ulApplicationTimeHook( void )
     {
-        return time( NULL );
+        return ( uint32_t ) time( NULL );
     }
 #endif